The secondary structure of the 5' end of a subset of eukaryotic mRNAs plays arole in the control of translation of those messages. Polyhedrin and P10 are two Baculovirus genes that are expressed at exceptionally high levels late during infection. Baculovirus expression systems have been extensively used to express foreign genes cloned behind the Polyhedrin and P10 promoters. Retaining about 35 amino acids of the polyhedrin gene in the recombinant virus improves the yield of the foreign protein. An investigation of the secondary structure of the 5' end of the two mature messages may reveal common features whose role in the control of translation could be determined experimentally.